Skin cleaning agents, a process for their production and their use

ABSTRACT

The present invention relates to hydrous, liquid, paste- or cream-like skin cleaning agents for the removal of strongly adhering soil, comprising anionic and/or amphoteric and/or non-ionogenic surfactants as washing-active substances, thickeners, at least one abrasive, and, optionally, adjuvants for the regulation of consistency, appearance, odor, and stability, such as pigments, fragrances, stabilizers, and preservatives, which skin cleaning agents are characterized by the fact that they comprise di-n-butyl adipate and/or diisopropyl adipate as the exclusive solvents. These agents are obtained by homogeneously mixing the components, optionally under heating of the mixture. If a C 8  -C 16  fatty alcohol which acts as consistency regulator is added, heating of the component mixture may be omitted. Besides, the addition of the fatty alcohol increases the detergent action. The present invention further relates to the use of these skin cleaning agents, with the cleaning agent being distributed on the skin without water or with a small amount of water first, and the cleaning procedure being continued and finished under rinsing with water.

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

The present invention relates to skin cleaning agents having an improved cleaning action and a gentle behavior to the skin. The present invention further relates to a process for their production and to the use of the agents as flowable hand cleaning agents and heavy-duty hand cleaning agents.

DISCUSSION OF THE BACKGROUND

Hand cleaning agents, in particular for the removal of strongly adhering dirt, have already been used in the industrial sector for some time. Patent application No. WO 91/14 420 describes cleaning agents which, in addition to anionic and/or non-ionogenic surfactants, comprise conventional abrasives, organic solvents in the form of carboxylic acid esters, in particular certain acetates, such as preferably n-butoxy-2-ethoxy-ethyl-acetate and fatty alkanolamides, fatty polyalkanolamides, the ethylene oxide and/or propylene oxide addition products thereof, as well as fatty acid monoglycerides as re-greasing agents. Another preferred, additionally used solvent in these hand cleansing agents is limonene, which is known to have a dermal incompatibility involving a sensitization risk. In order to produce the agents according to WO 91/14 420 in an efficient manner, it is necessary to heat the mixture to temperatures above 50° C. after mixing the raw materials, requiring additional heating energy and involving longer production periods.

Furthermore, hand cleaning agents are known which comprise as solvent component natural oils, such as olive oil, jojoba oil, maca-damia-nuts-oil, and grape-seed oil. These cleaning agents have limited detergent properties due to the interaction between the oil portions and the detergent portions and because of the low soil-removing capacity of the natural oil.

In cosmetics the use of special esters of the adipic acid is known. For instance, owing to its slightly greasing character, di-n-butyl adipate is used in day creams and liquid emulsions as well as in hair sprays and setting lotions as softening component or agent to achieve a superfatted state.

Patent No. GB 1,106,945 describes aqueous shampoo preparations for hair cleaning purposes; they comprise as solvents for fats alkyl esters of the dibasic carboxylic acids, phthalic acid or adipic acid. In hair cleaning and hair conditioning, particularly good results are obtained with dimethyl phthalate, however, there is no reference with respect to skin cleaning, in particular to the cleaning of skin heavily soiled by foreign substances.

EP 229 616 A2 describes bath additives comprising diisopropyl adipate as oil component which deposits on the skin.

EP 513 832 A1 describes pharmaceutical products comprising dibutyl adipate or a combination of dibutyl adipate and isopropyl myristate to improve or to control the skin penetration of a therapeutic agent.

Diisopropyl adipate is additionally used as lubricant in alcoholic lotions, as softener in hair aerosols and as fat factor in hair tonics and as solubilizer for perfumes.

PCT-application No. WO 92/09 265 describes a solvent-containing hand cleaning paste containing as solvent DBE 2, dimethyl adipate, dimethyl glutarate and dimethyl succinate, in an amount up to 54 parts per 100 parts of cleaning agent, as well as isooctyl stearate as additionally required re-greasing agent and bleached kernel or shell flour as mild abrasive.

In EP No. 0166522 A2 a cosmetic preparation for the removal of nail varnish is described, which has also skin cleaning properties and comprises as solvent for the nail enamel esters of dicarboxylic acids, preferably diesters or esters of diols, preferably dioldiesters. The diethyl esters of dicarboxylic acids having up to 6 C-atoms are preferred as dicarboxylic acid esters, and the diacetates of diols having 2 to 6-C-atoms are preferred as diol esters. Additionally, the preparations contain lanolin or other re-greasing components and no abradant.

For this reason, the use of the known solvents in skin cleaning agents has made it necessary until today to compensate their intense effect on the skin by the action of re-greasing agents. However, the detergent action of the surfactants is slightly affected by the re-greasing components.

SUMMARY OF THE INVENTION

Accordingly, there was the object to provide skin cleaning agents and a process for their production, whose solvents have a comparable or improved cleaning action and thus an action which intensifies the cleaning effect, as well as an improved dermatologic compatibility. Additionally, there was the object to find a process for the manufacture of skin cleaning agents, in which heating of the raw material mixture may be omitted.

These objects have been achieved by skin cleaning agents which comprise as exclusive solvents di-n-butyl adipate and/or diisopropyl adipate and which, parallel to this, comprise as major components washing-active substances, components for the improvement of consistency, appearance, odor and storage stability, as well as at least one abrasive and water, and the production of which may be effected by using certain fatty alcohols in order to improve the cleaning action and the production conditions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The subject matter of the present invention are hydrous, liquid, paste- or cream-like skin cleaning agents for the removal of strongly adhering dirt, which comprise anionic and/or amphoteric and/or non-ionogenic surfactants as washing-active substances, thickeners, at least one abrasive and, optionally, adjuvants for the regulation of consistency, appearance, odor, and stability, such as pigments, fragrances, stabilizers, and preservatives, and which are characterized in that they comprise di-n-butyl adipate and/or diisopropyl adipate as exclusive solvents. Known detergents are used as washing-active substances, in particular anionic and/or amphoteric and/or non-ionogenic surfactants, e.g., alkyl sulfates, alkyl sulfonates, alkyl ether sulfates, and fatty alcohol polyglycol sulfosuccinates, which are predominantly used in the form of their sodium salts, as well as the known non-ionogenic surfactants based on addition products of alkylene oxides to alkanols, alkanoic acids, which may also be capped at the end, and preferably alkyl polyglycosides.

Preferred surfactants include Na-lauryl ether sulfate, castor oil sulfonate, di-Na-lauryl polyglycol ether sulfosuccinate, cocoamidopropyl betaine, and alkyl polyglycosides having an alkyl residue of C₈ -C₁₆, preferably C₈ to C₁₀ and an oligoglycoside residue having an oligomerization degree of 1.1-1.7, preferably 1.2-1.3.

The portion of the active detergents amounts to 5-40%-wt., preferably 10-30%-wt., relative to the skin cleaning agent according to the present invention.

The portion of the esters di-n-butyl adipate and/or diisopropyl adipate in the agents according to the present invention amounts to 1-25%-wt., preferably 5 to 20%-wt., and particularly preferred 10-20%-wt.

Abrasives to be used with preference are the bleached kernel/shell flours according to WO 92/09265, in particular bleached walnut shell flour or olive kernel flour. The portion of the abrasive in the agent according to the present invention amounts to 1-30%-wt., preferably 10-20%-wt.

The agents according to the present invention further comprise viscosity forming agents, such as organophilic and/or hydrophilic phyllosilicates, such as bentonites, polysaccharides, such as cellulose and guar flour, as well as modified polysaccharides, such as the cellulose ethers, carboxymethylcellulose, and hydroxyethylcellulose and xanthan gum, and inorganic electrolytes, such as NaCl or MgSO₄. They further comprise chromatophoric pigments, such as TiO₂, stabilizers, such as propylene carbonate, pH-regulators, fragrances, and preservatives. The water content of the skin cleaning agents amounts to 10-50%-wt., preferably 20-40%-wt.

Re-greasing components may be omitted in the production of the skin cleansing agents according to the present invention. Preferably, the skin cleaning agents are obtained as liquid or creamy agents or as flowable viscous pastes.

According to another preferred embodiment, the skin cleaning agents according to the present invention additionally comprise at least one fatty alcohol of the general formula R-OH wherein R represents an alkyl residue having C₈ to C₁₆, preferably C₈ -C₁₂. The amount of the fatty alcohol in the agent amounts to 0.1-10.0%-wt., preferably 0.1-5.0%-wt.

The mentioned raw material components may usually also be employed by using combinations of one type of raw material, i.e., as mixtures of different surfactants, viscosity formers, abrasives, and stabilizers, etc.

The flowable skin cleansing agents are manufactured by means of known devices according to the batch or continuous method. Suitable devices are heatable vessels including an agitator, mixer and extruder, e.g., described in "Surfactants in Consumer Products", J. Falbe, Springer Verlag, 1987, page 399 ff.

The present invention further relates to a process for the production of the skin cleaning agents, in which the components are combined under stirring as usual, optionally using partial amounts of the raw materials, wherein the adipic ester solvents are preferably prepared first, and the pigment, viscosity forming agents/thickeners, and a partial amount of the surfactant are added then; this mixture is heated and preferably adjusted to a temperature of up to 70° C., preferably 40°-60° C., whereupon the remaining raw material amounts, in particular surfactants amounts, the inorganic electrolyte, the pH-regulator and fragrance, the preservative, and the abrasive are added. The homogeneous mixture is then cooled and filled into conventional vessels, such as cans, pump vessels, such as dispensers, jars, and tubes.

According to a special production method according to the present invention, fatty alcohols are added as consistency regulators to produce the agents. Most surprisingly, it was found that the addition of the fatty alcohol allows the mixing the raw materials, e.g., in the succession as mentioned above, to form homogeneous products at room temperature, i.e., at 5° to 30° C., without having to heat the raw material mixture. The fact that the heating phase is omitted and the involved saving of energy and time offer advantages with respect to process technology.

Moreover, the addition of the fatty alcohol has a positive effect on the use of the skin cleansing agents since, for example, the detergent effect is increased.

The skin cleaning agents according to the present invention are particularly suitable for the removal of rough dirt strongly adhering to the skin, e.g., fats, oils and other lubricants, dyes, varnishes, tar, graphite, soot, coloring pigments, and similar substances occurring in industry and public utilities, in the craftsmen's trade, or in agriculture and in the household.

The use of the skin cleaning agents according to the present invention is preferably effected by first distributing the cleaning agent on the skin without water or with a small amount of water, continuing the cleaning with water and finishing by rinsing with water. The small amount of water results by wetting or moistening the soiled skin areas with water or aqueous liquids. For instance, in the case of dirty hands, this quantity may amount to about 1 to 3 ml of water per palm.

The agents according to the present invention can easily be distributed on the skin during washing. They have a good foaming power and--compared to conventional products--a better detergent action, with the dirt being easily removed from the skin with water. In addition to the good soil removing capacity, the agents according to the present invention have an improved dermatological compatibility.

Owing to the use of suitable raw materials the agents are biodegradable and, for this reason, are characterized by a good ecological compatibility.

The invention will be illustrated by the following examples:

    ______________________________________     Formulation I     Di-n-butyl adipate      10.00%-wt.     Titanium dioxide        1.00%-wt.     Organophilic bentonite  2.10%-wt.     Carboxymethylcellulose  1.20%-wt.     Sulfated castor oil (70%)                             10.53%-wt.     Propylene carbonate     0.50%-wt.     Sodium fatty alcohol ether                             47.00%-wt.     sulfate (C.sub.12 -C.sub.15) 28%     Water                   0.19%-wt.     Di-sodium-lauryl polyglycol     ether sulfosuccinate (32-35%)                             10.00%-wt.     Common salt             2.00%-wt.     Citric acid             0.20%-wt.     Fragrance               0.20%-wt.     Preservative            0.08%-wt.     Walnut shell flour, bleached                             15.00%-wt.                             100.00%-wt.     Formulation II     Di-isopropyl adipate    10.00%-wt.     Titanium dioxide        1.00%-wt.     Organophilic bentonite  2.00%-wt.     Hydrophilic bentonite   3.00%-wt.     Alkyl polyglycoside (C.sub.8 -C.sub.10), 55%                             20.00%-wt.     Municipal water         1.89%-wt.     Citric acid             0.23%-wt.     Preservative            0.08%-wt.     Boiled salt             2.50%-wt.     Sodium fatty alcohol ether                             44.00%-wt.     sulfate (C.sub.12 -C.sub.15), 28%     Walnut shell flour, bleached                             15.00%-wt.     Fragrance               0.30%-wt.                             100.00%-wt.     Formulation III     Solvent a to g*)        10.00%-wt.     Titanium dioxide        1.00%-wt.     Hydrophilic bentonite   1.00%-wt.     Organophilic bentonite  4.00%-wt.     Alkyl polyglycoside (C.sub.8 -C.sub.10), 55%                             20.00%-wt.     Fatty alcohol (C.sub.8 -C.sub.12)                             1.50%-wt.     Municipal water         2.47%-wt.     Preservative            0.08%-wt.     Fragrance               0.30%-wt.     Citric acid             0.15%-wt.     Common salt             2.50%-wt.     Sodium fatty alcohol ether                             44.00%-wt.     sulfate (C.sub.12 -C.sub.15), 28%     Walnut shell flour, bleached                             13.00%-wt.                             100.00%-wt.     Formulation IV     Di-n-butyl adipate      10.00%-wt.     Titanium dioxide        1.00%-wt.     Hydrophilic bentonite   1.00%-wt.     Organophilic bentonite  3.00%-wt.     Alkyl polyglycoside (C.sub.8 -C.sub.10), 55%                             20.00%-wt.     Fatty alcohol (C.sub.8 -C.sub.12)                             4.00%-wt.     Municipal water         0.97%-wt.     Preservative            0.08%-wt.     Fragrance               0.30%-wt.     Citric acid             0.15%-wt.     Common salt             2.50%-wt.     Sodium fatty alcohol ether                             44.00%-wt.     sulfate (C.sub.12 -C.sub.15), 28%     Walnut shell flour, bleached                             13.00%-wt.                             100.00%-wt.     Formulation V     Di-n-butyl adipate      7.00%-wt.     Titanium dioxide        1.00%-wt.     Hydrophilic bentonite   1.00%-wt.     Organophilic bentonite  2.50%-wt.     Alkyl polyglycoside (C.sub.8 -C.sub.10), 55%                             20.00%-wt.     Fatty alcohol (C.sub.8 -C.sub.12)                             8.00%-wt.     Municipal water         0.47%-wt.     Preservative            0.08%-wt.     Fragrance               0.30%-wt.     Citric acid             0.15%-wt.     Common salt             0.50%-wt.     Sodium fatty alcohol ether                             44.00%-wt.     sulfate (C.sub.12 -C.sub.15), 28%     Walnut shell flour, bleached                             15.00%-wt.                             100.00%-wt.     ______________________________________      *)      IIIa: din-butyl adipate      IIIb: without solvent      IIIc: nparaffin      IIId: grapeseed oil      IIIe: DBE 2      IIIf: diisopropyl adipate      IIIg: din-butyl adipate, without fatty alcohol (C.sub.8 -C.sub.12)

The cleaning efficiency of the formulations was tested in the hand washing test according to the method described in DE 27 36 970 A1. It was found that the agents show a considerably improved cleaning action with respect to model soil mainly consisting of oil, wax, vaseline, graphite, lampblack, and iron oxide, and with respect to model varnish consisting of synthetic resin, fish oil, and a paint pigment.

The skin compatibility was tested in the Duhring chamber test Frosch, P. J., Kligman, A. M.: The Duhring chamber and improved technique for epicutaneous testing of irritant and allergic reactions. Contact Derm. 5, 73-81 (1979); Frosch P. J., Kligman, A. M.: The soap chamber test, a new method of assessing the irritancy of soaps. J. Am. Acad. Derm. 1, 35-41 (1979)!. The results show that the dermal compatibility of the agents according to the present invention, as compared to commercially known products, is also improved.

    __________________________________________________________________________     Hand washing test     __________________________________________________________________________     Test         Formulation     person         I  IIIc               I  IIId                     I  IIIa                           II IIIc                                 II IIId                                       II IIIa                                             IIIa                                                IIIb     __________________________________________________________________________     1   1.0            1.5               0.0                  0.5                     0.5                        0.0                           0.0                              0.5                                 1.0                                    1.0                                       1.0                                          0.0                                             0.5                                                0.5     2   0.5            0.5               0.5                  0.5                     0.5                        0.5                           0.0                              1.5                                 0.0                                    1.0                                       1.5                                          0.5                                             0.0                                                1.0     3   0.5            0.5               0.5                  1.0                     1.0                        0.5                           0.5                              1.5                                 0.5                                    1.5                                       1.0                                          0.5                                             0.0                                                2.0     4   0.5            1.0               1.0                  1.5                     1.0                        0.5                           1.0                              0.5                                 1.0                                    1.0                                       0.5                                          1.0                                             0.5                                                0.5     5   1.0            0.5               0.0                  0.5                     0.0                        0.5                           1.0                              1.0                                 1.0                                    1.0                                       0.5                                          0.5                                             0.0                                                1.0     6   0.5            1.5               0.5                  0.5                     0.5                        0.5                           0.5                              0.5                                 0.5                                    0.5                                       0.0                                          0.5                                             0.1                                                0.5     Average         0.6            0.9               0.4                  0.8                     0.6                        0.4                           0.5                              0.9                                 0.7                                    1.0                                       0.8                                          0.5                                             0.3                                                0.9     __________________________________________________________________________     Test         Formulation     person         IIIa            IIIc               IIIa                  IIId                     IIIa                        IIIe                           IIIa                              IIIf                                 IIIa                                    IIIg                                       IIIf                                          IIIe                                             IIIf                                                IIId     __________________________________________________________________________     1   0.5            0.0               0.0                  1.5                     0.5                        0.5                           1.0                              2.0                                 0.0                                    1.5                                       0.5                                          0.5                                             0.5                                                1.0     2   0.5            0.0               0.0                  0.5                     0.0                        0.5                           1.0                              1.0                                 0.5                                    1.0                                       0.0                                          0.5                                             0.5                                                0.5     3   0.5            1.0               0.0                  1.0                     1.5                        1.0                           0.5                              0.5                                 0.5                                    1.0                                       1.5                                          1.0                                             1.0                                                1.5     4   0.5            0.5               1.0                  0.5                     0.5                        1.0                           0.0                              1.0                                 0.5                                    1.0                                       1.0                                          0.5                                             0.5                                                0.5     5   0.5            2.5               0.0                  0.5                     1.5                        1.0                           0.5                              0.5                                 0.0                                    1.0                                       2.0                                          1.5                                             1.5                                                2.5     6   0.5            2.0               1.0                  1.0                     2.0                        2.5                           2.0                              1.5                                 1.5                                    1.5                                       0.5                                          0.0                                             1.0                                                1.0     Average         0.5            1.0               0.3                  0.8                     1.0                        1.1                           0.8                              1.1                                 0.5                                    1.2                                       0.9                                          0.7                                             0.8                                                1.2     __________________________________________________________________________     IIIa: Formulation with di-n-butyl adipate     IIIb: Formulation without solvent     IIIc: Formulation with n-paraffin     IIId: Formulation with grape-seed oil     IIIe: Formulation with DBE2     IIIf: Formulation with di-isopropyl adipate     IIIg: Formulation with di-n-butyl adipate without fatty alcohol (C.sub.8     -C.sub.12)     Amount of test product:                1.2 g     Amount of dirt:                0.5 g

Result

Both, formulation I with di-n-butyl adipate and formulation II with di-isopropyl adipate have a better detergent action than IIIc and IIId, but a slightly worse action than IIIe.

The washing tests clearly show the superiority of the formulation IIIa comprising di-n-butyl adipate and fatty alcohol (C₈ -C₁₂), as compared with those without solvent (IIIb), with di-n-butyl adipate (IIIg), with n-paraffin (IIIc) and grape-seed oil (IIId).

In comparison with the formulations comprising DBE 2 (mixture of dimethyl adipate, dimethyl succinate, dimethyl glutarate), IIIe, and di-isopropyl adipate, IIIf, IIIa has a comparable or better detergent action.

Additionally, the formulation comprising diisopropyl adipate, IIIf, has a better cleaning effect than that comprising grape-seed oil, IIId, but a slightly worse one than the formulation with DBE 2, IIIe.

    ______________________________________     Duhring-Chamber-Test     ______________________________________              NaLS Formulation           Water    0.5%   I     II   IV    V    IIIb     ______________________________________     A-value           25.1     4.3    16.1  14.4 14.8  15.3 14.2     ______________________________________             NaLS Formulation           Water   0.5%   IIIa IIIc IIId IIIe  IIIf IIIg     ______________________________________     A-value           25.1    4.3    15.2 5.0  17.1 8.2   14.7 14.5     ______________________________________     IIIa: Formulation with di-n-butyl adipate     IIIb: Formulation without solvent     IIIc: Formulation with n-paraffin     IIId: Formulation with grape-seed oil     IIIe: Formulation with DBE2     IIIf: Formulation with di-isopropyl adipate     IIIg: Formulation with di-n-butyl adipate without fatty alcohol (C.sub.8     -C.sub.12)     Amount of test product:                  appr. 200 mg     Duration of test:                  3 weeks     Application intervals:                  1st day 2 hours                  2nd day 4 hours                  3rd day 6 hours                  4th day 6 hours                  5th day about 5 hours     Number of test persons:                  25

Result:

The Duhring Chamber Test proves the good dermal compatibility of the formulations according to the present invention I, II, IV, IIIa, IIIf, and IIIg for this product class. In comparison, the formulations with n-paraffin (IIIc) and DBE 2 (IIIe) show a considerably worse skin compatibility. 

We claim:
 1. A skin cleaning agent in hydrous, liquid, paste, or cream form comprising:1-25%-wt. of di-n-buytl adipate, di-isopropyl adipate, or a mixture thereof, as the only non-aqueous solvent component, a surfactant selected from the group consisting of anionic, amphoteric, nonionic surfactants and mixtures there of, wherein the content of surfactant amounts to 5-40%-wt., relative to the skin cleaning agent, a thickener in an amount to affect the viscosity of the skin cleaning agent, 0.1 to 10.0%-wt. of at least one fatty alcohol of the formula R--OH wherein R is alkyl having C₈ to C₁₆, 1-30%-wt. of at least one abrasive, and optionally, one or more pigments, fragrances, stabilizers and preservatives.
 2. The skin cleaning agent according to claim 1, comprising alkyl polyglycosides having an alkyl of C₈ to C₁₆ and an oligoglycoside with an oligomerization degree of 1.1 to 1.7 as a nonionic surfactant, sodium fatty alcohol ether sulfate as an anionic surfactant and bleached walnut shell flour as an abrasive.
 3. The skin cleaning agent according to claim 2, wherein said alkyl polyglycosides have a C₈ -C₁₀ alkyl.
 4. The skin cleaning agent according to claim 2, wherein said oligoglycoside has an oligomerization degree of 1.2-1.3.
 5. The skin cleaning agent according to claim 1, wherein water is present in amounts of 10-50%-wt.
 6. The skin cleaning agent according to claim 5, containing 20-40%-wt. water.
 7. A process for the production of the skin cleaning agent as defined in claim 1, comprising preparing the solvent first, adding the pigment, thickener and a partial amount of the surfactant, heating the mixture thus obtained to a temperature of up to 70° C., adding the remaining amounts of components, followed by homogenization and final cooling.
 8. The process according to claim 7 wherein the mixing of the components and the homogenization is effected without heating.
 9. The process according to claim 7, wherein said mixture is heated to a temperature of 40°-60° C.
 10. The process according to claim 7, wherein said components comprise surfactant, inorganic electrolyte, pH-regulator, fragrance, preservative and abrasive.
 11. A method of cleansing the skin, wherein during cleansing the cleaning agent of claim 1 is distributed on the skin, and the cleaning procedure is finished under rinsing with water.
 12. The skin cleaning agent according to claim 1, wherein R is C₈ -C₁₂ alkyl.
 13. The skin cleaning agent according to claim 1, comprising 5-20%-wt. of solvent.
 14. The skin cleaning agent according to claim 1, containing 0.1-5.0%-wt. fatty alcohol.
 15. The skin cleaning agent according to claim 1, containing 10-30%-wt. of surfactant.
 16. The skin cleaning agent according to claim 1, containing 10-20%-wt. abrasive. 